Compilare: user.cpp: In function ‘int main()’: user.cpp:6:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cal.in","r",stdin); ^ user.cpp:7:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cal.out","w",stdout); ^ user.cpp:8:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d", &sx, &sy, &s, &n); nr=0; ^ user.cpp:10:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^